1. Field of the Invention
The present invention generally relates to a data storing and reading apparatus, and more particularly, to a data storing and reading apparatus for electrically recording and storing data in a nano device that uniform size of nano-dots are regularly arranged and reading the data from the nano device.
2. Discussion of Related Art
There have been several kinds of data storing and reading apparatuses, a magnetic storage device, an optical storage device and an electronic storage device. The magnetic storage device is commonly used for a large amount of data and the optical storage device is mainly for potable electronic devices.
Recently, electronic storage devices such as a flash memory which stores data using electric signals are developed and getting rapidly popularized due to rapid technical progress and cost reduction. However, all the conventional data storage devices have problems below.
As for the magnetic storage device, the maximum storage density is limited due to superparamagnetic limit even though sensitivity of a sensor is highly increased. The optical storage device can not increase its maximum storage density due to diffraction limit determined by wavelength of light and numerical aperture of a lens. As for the electronic storage device, since a storage medium for storing the electric signal is not limited in size, storage density can be increased to a great extent as long as the sensitivity of the sensor for detecting electrical charges is increased.
The electrical data storing is accomplished by injecting electrical charges into a SiNxOy layer for a flash memory and using dielectric polarization of a ferroelectric material with a high dielectric constant for a ferroelectric random access memory (FRAM). However, the flash memory has problems that it is difficult to control storage density since the charge injection area exists in a trap state of an interface of the SiNxOy layer and it exhibits fatigue as the storing operations are repeated. The FRAM has a problem that as a size of the ferroelectric material decreases, polarization intensity is reduced and ferroelectricity will be lost. Further, imprint and retention of the FRAM are degraded due to hydrogen-induced thermal damage caused during manufacturing processes and repeated storing operations.